Vitamin K2 (MK-7) — Mechanism, Benefits, Dosing

Overview

A fat-soluble vitamin in the K2 family. MK-7 has a 72-hour half-life vs <12 h for MK-4. Activates osteocalcin (bone) and matrix Gla protein (arteries).

Natural sources

Natto (richest source)
Aged cheeses (Gouda, Brie)
Egg yolks
Liver

Common forms

MK-7 (long half-life, daily dose)
MK-4 (shorter half-life, larger doses)

Mechanism of action

K2 is the cofactor for γ-glutamyl carboxylase, which carboxylates osteocalcin (binds Ca to bone) and matrix Gla protein (prevents arterial calcification).

Pathways

· γ-carboxylation of Gla proteins
· Bone mineralization
· Arterial calcification prevention

Enzymes

· γ-glutamyl carboxylase

Effects on the body

Supports

Bone mineralization

Decreases

Arterial calcification progression

Supports

Osteocalcin activation

Organ system effects

Bones

Activates osteocalcin → drives Ca into bone matrix.

Cardiovascular

Activates matrix Gla protein → inhibits vascular calcification.

Evidence-based benefits

Reduces arterial stiffness in postmenopausal women

Moderate evidence

Reduces vertebral fracture risk

Moderate evidence

Improves bone mineral density (with D3 and Ca)

Moderate evidence

Potential side effects

Common

· None at typical doses

Rare

· Mild GI upset

Serious

· Interferes with warfarin INR control

Drug interactions

Warfarin

K2 directly reverses warfarin's anticoagulant effect.

severe

Bile-acid sequestrants

Reduces absorption.

minor

Safety & non-supplemental interactions

Educational summary — always confirm with your clinician or pharmacist before starting, stopping, or combining with prescription therapy.

Avoid / monitor with these medications

·Warfarin — directly antagonizes anticoagulant effect; do not start/stop without monitoring INR

Supplement interactions

Pairs well with

Vitamin D3
D3 drives Ca absorption; K2 directs it to bone, not arteries.
Magnesium + Calcium
Full bone-health stack.

Avoid combining with

Warfarin (unless monitored)
Reverses anticoagulation.

Dosing & bioavailability

Typical dose

100–200 mcg MK-7/day

Study range

45–360 mcg MK-7; 1,500 mcg–45 mg MK-4

Upper safe limit

No defined UL; well tolerated up to 360 mcg MK-7

Best form

MK-7 (trans-isomer, ≥99%) for once-daily dosing

Timing

With largest fatty meal

With food?

Fat-soluble — requires dietary fat

Where to buy

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Scientific evidence (10)

RCTThrombosis and Haemostasis · 2015

MK-7 supplementation improves arterial stiffness in healthy postmenopausal women

Knapen MH, et al.

Double-blind RCT, 244 postmenopausal women, 180 mcg MK-7/day × 3 years.

Key findings

Significant improvement in carotid stiffness (β-stiffness index) vs placebo.

Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: Vitamin K2 (MK-7) — Reduces arterial stiffness in postmenopausal women

Live PubMed search

Live results for "Vitamin K2 (MK-7) Reduces arterial stiffness in postmenopausal women" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching Vitamin K2 (MK-7) and "Reduces arterial stiffness in postmenopausal women". Filter by RCT, meta-analysis, or year on the results page.

Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: Vitamin K2 (MK-7) — Reduces vertebral fracture risk

Live PubMed search

Live results for "Vitamin K2 (MK-7) Reduces vertebral fracture risk" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching Vitamin K2 (MK-7) and "Reduces vertebral fracture risk". Filter by RCT, meta-analysis, or year on the results page.

Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: Vitamin K2 (MK-7) — Improves bone mineral density

Live PubMed search

Live results for "Vitamin K2 (MK-7) Improves bone mineral density" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching Vitamin K2 (MK-7) and "Improves bone mineral density". Filter by RCT, meta-analysis, or year on the results page.

Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: Vitamin K2 (MK-7) — randomized controlled trial

Live PubMed search

Live results for "Vitamin K2 (MK-7) randomized controlled trial" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching Vitamin K2 (MK-7) and "randomized controlled trial". Filter by RCT, meta-analysis, or year on the results page.

Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: Vitamin K2 (MK-7) — meta-analysis

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Live results for "Vitamin K2 (MK-7) meta-analysis" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching Vitamin K2 (MK-7) and "meta-analysis". Filter by RCT, meta-analysis, or year on the results page.

Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: Vitamin K2 (MK-7) — pharmacokinetics

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Live results for "Vitamin K2 (MK-7) pharmacokinetics" across the PubMed/MEDLINE peer-reviewed index.

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Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: Vitamin K2 (MK-7) — safety adverse events

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Live results for "Vitamin K2 (MK-7) safety adverse events" across the PubMed/MEDLINE peer-reviewed index.

Key findings

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Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: Vitamin K2 (MK-7) — dose response

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Live results for "Vitamin K2 (MK-7) dose response" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching Vitamin K2 (MK-7) and "dose response". Filter by RCT, meta-analysis, or year on the results page.

Open study

Systematic reviewGoogle Scholar · 1970

Google Scholar: Vitamin K2 (MK-7) — clinical evidence

Live Scholar search

Cross-database citation index for Vitamin K2 (MK-7) as it relates to "clinical evidence".

Key findings

Includes preprints, theses, and journal articles. Useful for tracking citation counts and follow-on work.

Open study

Educational use only. This profile is not medical advice. Consult a qualified healthcare professional before starting any supplement, especially if you take prescription medication or have a chronic condition.